There are 2 things here, memory and disc space. Memory only stores what it does whilst the machine is on,.Your photos are files stored on the disc. When they are deleted they are not actually removed all that happens is a flag is set in the Disc's internal directory to tell it that the space you file was using is now available for use.There are programs such as Norton unerase that will read the directory and reset the flag so they can be retrieved but only if the space has not been used. That is why there are special delete programs out there for secure deletion. The recycle bin is just another folder set up as a holding area so the delete process is idiot proof.